What number should replace the question mark?

What number should replace the question mark?

 

Answer:

8: each number in the segment at the bottom is the sum of the four numbers in the sections either side. Thus: 8 + 3 + 4 + 3 = 18.

What number should replace the question mark?

What number should replace the question mark?

 

Answer:

7: 91 ÷ 13

What number should replace the question mark?

What number should replace the question mark?

1, 101, 15, 4, 29, –93, 43, –190, ?

 

Answer:

57: there are two alternate sequences: +14, –97

What number should replace the question mark?

Answer: 5: (8 + 7) × 5 = 75

What number should replace the question mark?

What number should replace the question mark?

52, 25, 77, 77, ? , 451, 605

Answer:

154: reverse the previous number and add; for example 52 reversed is 25, and 52 + 25 = 77